A dibasic acid ester as is normally used as a synthetic lubricant base stock is an ester of a straight-chain dibasic acid, such as adipic, azelaic or sebacic acid, and a long-chain branched primary alcohol usually having eight to thirteen carbon atoms. The alcohol typically utilized is an "oxo" alcohol. See, for example "Synthetic Lubricants", Report No. 125, Process Economics Program, May, 1979, pp. 105 et seg., SRI International.
The Dimersol Process is a catalyzed liquid phase oligomerization of lower olefins, particularly propylene and butylene. The catalyst is formed by reacting a nickel compound with a hydrocarbyl aluminum halide. The primary product is the dimer with smaller amounts of the trimer and tetramer being present. General discussion of the Dimersol Process can be found in Hydrocarbon Processing, Vol. 89, pp 143-149, May, 1980 and Vol. 91, pp 110-112, May, 1982. The higher oligomers are quite useful for converting to alcohols and reacting with adipic acid to form adipate esters which are useful as lubricants. The instant invention relates to a process to enhance and augment the higher olefin oligomers whereby when they are converted to adipate esters, said esters have improved properties.